Biodegradable or degradable film bag for the placement of concrete or formation of concrete repairs in and around watercourses

ABSTRACT

The invention relates to a bag used for the placement of concrete or grout, either hand placed or pump filled, in and around watercourses. The bags are impermeable and contained in nature, made of biodegradable, degradable or water soluble polymer film, typically made from renewable starch based polymers or water soluble polymers. The bags offer a means of easily and simply placing concrete or grout, safely, cleanly and without risk of contamination to the watercourse or environment from cement leakage, being impermeable in nature, whilst allowing the polymer film to safely degrade, dissolve or disintegrate, in the environment, without the risk of unsightly or environmentally detrimental polythene waste being placed in the watercourse.

CROSS-REFERENCE TO APPLICATIONS

This Application claims the benefit of foreign priority under 35 USC§119 of GB Patent Application 0819163.7, filed Oct. 20, 2008, the entirecontent of which is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates bags and, in particular, to a bag used forthe placement of concrete or grout, either hand placed or pump filled,in and around watercourses.

BACKGROUND AND SUMMARY

There are many instances in which concrete needs to be placed in oraround watercourses, for example, in order to repair or protect bridgesfrom undermining or scour.

Simple, hand-placed, concrete filled hessian bags, similar to sand bags,have traditionally served this function, to enable the placementconcrete in rivers for example, however, the open weave of the fabricallows the escape of cement fines into the water which can result inpollution. As a consequence, strict environmental legislation hasresulted in their disfavour with environmental consulting bodies.

A range of other fabrics have been used to overcome these problems,utilising for example, a dense weave or coated fabrics, to provide animpermeable component to the fabric to better contain the concretewithin the bag. These bags, due to their fabric nature, are typicallysewn and in order to contain a sealed and impermeable nature have formalinlets and closure points, typically involving plastic components. As aresult, this contained impermeable form of bagwork tends to beconsiderably more costly to manufacture than traditional hessian bags.

Another form of bag currently used, utilises paper. In this instance,bags containing dry sand/cement for example, can be placed in or aroundwater. The sand/cement slowly absorbs external water through the paperbag to slowly cure the sand/cement mix, to form a hardened block. Thepotential for rips or tears and subsequent spillage of wet or drymaterial is however significant.

The invention described herein attempts to match the impermeable natureof coated fabric bags, instead utilising biodegradable or degradablepolythene or polymer film, to form the bag lining. In this reference,polythene (adj) refers to any polymer that can be moulded when hot, andnot just as an abbreviation of polyethylene. The biodegradable ordegradable bag is typically made of corn or potato starch, or similarnatural renewable polymer, a traditional fossil fuel polymer based filmwith additional catalysts that allow rapid physical degradation, or awater soluble polymer such as poly vinyl alcohol.

Biodegradable polymer film can also degrade rapidly, with the use ofmicro-organisms, with both biodegradable or degradable forms breakingdown over a period of typically weeks to months, into carbon dioxide,water and methane. The ultimate result is that the polymer film andbagwork degrades and disappears, in a safe and non-polluting manner.

For the function of placing concrete in water, the use of biodegradable,degradable or watersoluble polymer film to form the bags has severaladvantages. Firstly, the impermeable nature of the polymer film meansthat unlike hessian, no cement fines can escape the bag, preventingcement pollution from escaping into the environment. The polymer filmsuccessfully achieves the primary role of containing the concrete andforming a concrete block, without allowing cement fines to escape out ofthe bag. Secondly, the use of polymer film means that seams can be gluedor heat welded, eliminating the need for sewing for the bulk, if notall, of the bag that would typically be required for fabrics. Bags couldtherefore be mass-produced, using machines, significantly cheaper thansewn bags.

Finally, having a bag or “formwork” made from a material that breaksdown in an environmentally safe manner means that within a relativelyshort period of time, all traces of the bag have disappeared, withoutlooking tattered or unsightly and without causing adverse environmentalimpact or pollution. This is particularly true for starch-based polymerfilm, made from renewable natural resources, and water soluble forms ofpolymer film. It is important to appreciate the fact that bags used forthe placement of concrete below water are permanent and remain inposition after the blockwork has formed. Non-biodegradable polymer film,typically traditional oil based polythene, could conceivably be used forthe bags, to place the concrete in an impermeable manner, however, thepolythene would be unsightly and have a negative and very long termimpact on any environment. Using renewable biodegradable polymer basedpolymer film, typically formed from corn, potato, tapioca or wheatstarch, for example, or various forms of water soluble polymer, forexample poly vinyl alcohol, will have many environmental benefits andimportantly allow the use of polymer films in this application.

According to one aspect, a biodegradable or degradable film bag isdescribed for the placement of concrete or formation of concrete repairsin and around watercourses. The bag is formed from a biodegradable ordegradable polymer film forming a fully impermeable means of containmentto allow concrete or grout to be placed safely in or aroundwatercourses.

The biodegradable or degradable film bag can be specifically filled withsaid concrete or grout and then placed by hand in its intended finalposition. The film material can be made from corn, potato, tapioca,wheat or similar derived natural renewable polymer. The closure of thebag can be provided by sewing the top of the bag, Ziploc or similarmeans. The closure of the bag can be provided by a formal inlet,incorporating a push-in or threaded closure cap or plug. The film bagcan be formed into extensive mattresses and pump filled with grout,concrete or similar cementitious material. The concrete or grout placedwithin the bags can be in its wet state or its dry or semi-dry state.The film bag can be placed within a simple hessian, jute or similarnatural fabric bag, to give the appearance of a woven fabric bag. Thepolymer forming the film can be specifically a water soluble polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will now be described withreference to the accompanying drawings in which:

FIG. 1 shows a typical open-ended bag, in section and profile;

FIG. 2 shows the sequence of filling and closure;

FIG. 3 shows several options for closure; and

FIG. 4 shows how typically the bags are placed below water, in thisinstance to underpin an undermined wall or abutment.

DETAILED DESCRIPTION

The particular values and configurations discussed in these non-limitingexamples can be varied and are cited merely to illustrate at least oneembodiment of the present invention and are not intended to limit thescope of the invention.

FIG. 1 shows a biodegradable or degradable film bag, 1, in both frontand side elevations, with the top end open but the opposing side, 2,sealed, in this instance with a heat weld. Gussets, 3, are formed alongthe sides, to allow expansion of the bag, when filled.

FIG. 2 shows a typical sequence of filling, showing an empty, open-endedfilm bag, 4, subsequently filled with concrete, 5, then sealed along theopen end, in this example with a simple sewn line of stitching.

FIG. 3 shows possible forms of closure along the top edge. For bags withan open top edge, these include a simple sewn stitch line, 7, or aZiploc closure, 8. Alternatively, a fully closed bag can be formed,including a formal inlet, 9, in this embodiment shown with a circularthreaded closure that utilises a threaded closure cap or plug. For anembodiment incorporating a formal inlet of this nature, both ends of thebag are sealed, in this instance with a heat weld.

FIG. 4 shows how the hand placed bags are typically used and placed,once the bags are filled with concrete or grout, and closed in a mannershown in FIG. 3. the filled bags, 11, are placed, in this instance, tofill a void, 12, beneath an undermined bridge abutment, 13, below water.

The embodiments and examples set forth herein are presented to bestexplain the present invention and its practical application and tothereby enable those skilled in the art to make and utilize theinvention. Those skilled in the art, however, will recognize that theforegoing description and examples have been presented for the purposeof illustration and example only.

Other variations and modifications of the present invention will beapparent to those of skill in the art, and it is the intent of theappended claims that such variations and modifications be covered.

The description as set forth is not intended to be exhaustive or tolimit the scope of the invention. Many modifications and variations arepossible in light of the above teaching without departing from the scopeof the following claims. It is contemplated that the use of the presentinvention can involve components having different characteristics.

1. A biodegradable or degradable film bag for the placement of concreteor formation of concrete repairs in and around watercourses, where thebag is formed from a biodegradable or degradable polymer film forming afully impermeable means of containment to allow concrete or grout to beplaced safely in or around watercourses.
 2. A biodegradable ordegradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claim 1,where the bags are specifically filled with said concrete or grout andthen placed by hand in its intended final position.
 3. A biodegradableor degradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claim 1,where the film material is made from corn, potato, tapioca, wheat orsimilar derived natural renewable polymer.
 4. A biodegradable ordegradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claims 2,where the film material is made from corn, potato, tapioca, wheat orsimilar derived natural renewable polymer.
 5. A biodegradable ordegradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claim 1,where closure of the bag is provided by sewing the top of the bag,Ziploc or similar means.
 6. A biodegradable or degradable film bag forthe placement of concrete or formation of concrete repairs in and aroundwatercourses, as claimed in claim 2, where closure of the bag isprovided by sewing the top of the bag, Ziploc or similar means.
 7. Abiodegradable or degradable film bag for the placement of concrete orformation of concrete repairs in and around watercourses, as claimed inclaim 1, where closure of the bag is provided by a formal inlet,incorporating a push-in or threaded closure cap or plug.
 8. Abiodegradable or degradable film bag for the placement of concrete orformation of concrete repairs in and around watercourses, as claimed inclaim 2, where closure of the bag is provided by a formal inlet,incorporating a push-in or threaded closure cap or plug.
 9. Abiodegradable or degradable film bag for the placement of concrete orformation of concrete repairs in and around watercourses, as claimed inclaim 1, where the film bag is formed into extensive mattresses and pumpfilled with grout, concrete or similar cementitious material.
 10. Abiodegradable or degradable film bag for the placement of concrete orformation of concrete repairs in and around watercourses, as claimed inclaim 1, where the concrete or grout placed within the bags is in itswet state.
 11. A biodegradable or degradable film bag for the placementof concrete or formation of concrete repairs in and around watercourses,as claimed in claim 2, where the concrete or grout placed within thebags is in its wet state.
 12. A biodegradable or degradable film bag forthe placement of concrete or formation of concrete repairs in and aroundwatercourses, as claimed in claim 1, where the concrete or grout placedwithin the bags is in its dry or semi-dry state.
 13. A biodegradable ordegradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claim 2,where the concrete or grout placed within the bags is in its dry orsemi-dry state.
 14. A biodegradable or degradable film bag for theplacement of concrete or formation of concrete repairs in and aroundwatercourses, as claimed in claim 1, whereby the film bag can be placedwithin a simple hessian, jute or similar natural fabric bag, to give theappearance of a woven fabric bag.
 15. A biodegradable or degradable filmbag for the placement of concrete or formation of concrete repairs inand around watercourses, as claimed in claim 2, whereby the film bag canbe placed within a simple hessian, jute or similar natural fabric bag,to give the appearance of a woven fabric bag.
 16. A biodegradable ordegradable film bag for the placement of concrete or formation ofconcrete repairs in and around watercourses, as claimed in claim 1,whereby the polymer forming the film is specifically a water solublepolymer.
 17. A biodegradable or degradable film bag for the placement ofconcrete or formation of concrete repairs in and around watercourses, asclaimed in claim 2, whereby the polymer forming the film is specificallya water soluble polymer.